For a long time, i've been wondering about this obvious yet intriguing phenomenon. I have a question for you biology folks....

Q:When a normal person is introduced to sudden physical pain(preferably sharp), why does he\she shout? We know that it is an involuntary action, but why does the body engage that involuntary action?

I'm a physics student and i've come up with a theory of my own. Here goes:-

For instance, let us assume that you have a vessel of boiling water(say >400k). You insert your finger into the hot water. As the kinetic energy of the molecules inside the vessel is very high, the energy gets transferred to your finger as the molecules collide on your finger. Now, (Here's the fussy part) assuming that the energy gained by our body in this process is not negligible w.r.t the enrgy already contained in our body, the newly acquired energy will disturb the body's Energy-stability equilibrium, causing the body's stability to decrease(as we know stability is inversely proportional to energy). To regain the body's instantaneous loss stability, the body has to engage a mechanism through which it can *quickly* loose energy. And that mechanism,ladies and gentlemen,is nothing but the release of energy to the air molecules around our voice box which is termed as shouting. Now my theory can be assumed valid, taking into considerstion the fact that the amount of energy acquired is directly proportional to the intesity of your shout( if you think i'm kidding try it on yourself)

haha typical physics student
anyways, though it is a good attempt at an explanation, I don't think the body shouting has to do with energy stability. Interesting theory though, nonetheless

this is why I don't think it would work, other than your above listed reasons. What about different people's pain thresholds. Not all people will feel the same amount of pain. They will also not shout as loud. I believe this is a little different than energy. I don't understand it myself, but would be interested at some other theories.

This is typical biology student's reply which i did expect, but not a one which answers my question.

>What about different people's pain thresholds. Not all people will feel the same amount of pain. They will also not shout as loud<

I agree that people's pain thresholds are different and they won't shout alike. But what i meant when i said "the amount of energy acquired is directly proportional to the intesity of your shout" was that when the experiments are conducted on the *same* person, the pain will be directly proportional to the loudness; but yes, it does depend on lot of other factors like the mood of the person, source of pain etc.

But my question is more fundamental.
"Why do we shout when introduced to pain?".

> I don't think the body shouting has to do with energy stability. Interesting theory though, nonetheless<

Let my theory be irrelevant, But what i really want is a reasonable explanation from biological point of view.

>Shouting being accompanied to pain is useful - it allows the 'victim' to let other people know they've been hurt immediately and highlights the event as being harmful.<

Are you really a biology student?

We know that reflexes are'nt voluntary actions. Besides, We have lesser free-will than you think we have. Which means you don't shout after being bitten by a mad dog *after* thinking "Okay, now if i shout maybe people will come to my rescue..."
It is just that the thinking never happens.

I didn't say the shouting was voluntary and I'm not trying to imply that a person stops, and thinks - woah, i've really burnt myself there, best tell the others...

Think about the evolutionary advantage of linking the perception of pain with a vocal reaction. At first it was an advantage for organisms to let each other know not to follow suit or to let them know they were injured.

As for higher organisms such as ourselves, our pain perception has been linked with emotion - so we shout, scream and cry to let others know the extent of our injury. That's why I think we have shouting linked with pain, not because molecules have gained kinetic energy and need to release it over our vocal cords.

[quote="pd84"]I didn't say the shouting was voluntary and I'm not trying to imply that a person stops, and thinks - woah, i've really burnt myself there, best tell the others...

>Think about the evolutionary advantage of linking the perception of pain with a vocal reaction. At first it was an advantage for organisms to let each other know not to follow suit or to let them know they were injured.<

you're talking about the grunting of cavemen, which is not actually shouting, but communicating...

>As for higher organisms such as ourselves, our pain perception has been linked with emotion - so we shout, scream and cry to let others know the extent of our injury. <

Okay, imagine this situation, You're hiding from a mad gang of murderers and you have to avoid their knowledge of your presence at any cost.

In this situation where the gang is right near you, suddenly you're being poked with a sharp pin. Would you still let the others know of your pain?

Okay, if you were talking about the changes that evolution has brouhght about, Here's a fact that i have noticed.... **Shouting actually helps reduce the pain***....Not fully though, but marginally; which goes well with my theory.

Although cavemen isn't what i meant, whether they grunted or shouted, the point is that a form of involuntary communication (grunt or shout) was linked with the perception of pain for the reasons I've stated.

In the situation of hiding, what would happen with this extra energy that has reduced your stability if you couldn't shout? Plus, you've already stated yourself that the shout of pain is involuntary - so would I have a choice to let people know of my pain?

<In the situation of hiding, what would happen with this extra energy that has reduced your stability if you couldn't shout? >

According to my theory, that extra energy would result in more pain. i.e. more than what it would have been if you have shouted.

<Plus, you've already stated yourself that the shout of pain is involuntary - so would I have a choice to let people know of my pain?>

That's exactly what i was trying to prove.

Look i'm not trying to prove my stupid theory here. What i'm trying to do is get a better explanation. My theory has 1/100 probability of being correct because this is more of a biological phenomenon than a physical one. So, if you can get any answers from you rmentors or some of the biology experts you know, it would be great. I was expecting more responses for this thread.

Anyway can you not explain this phenomenon based on step by step analysis like it happens in physics rather than let intiution take over? And do you agree with the statement that shouting helps reduce the pain marginally?

<well, what would happen when you dip the finger of a person who is in a coma?>

You have'nt read my question in the first post i guess.

Anyway, i think that 'Coma' is the term given to a person who is unconnected to the present physical world that he\she is in. which means he\she would'nt have his "input devices"(eyes,ears,nose,skin & tongue) connected to his\her processor(Brain).

As all the reflexes are consequences of the defense mecahnism engaged by the processor, the reflex actions would never happen. i.e. the processor would'nt recieve the inputs which it requires for processing; therefore it would'nt give the outputs.